Buried Soldiers May Be Victims of Ancient Chemical Weapon

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Almost 2,000 years ago, 19 Roman soldiers rushed into a cramped
underground tunnel, prepared to defend the Roman-held Syrian city
of Dura-Europos from an army of Persians digging to undermine the
city's mudbrick walls. But instead of Persian soldiers, the
Romans met with a wall of noxious black smoke that turned to acid
in their lungs. Their crystal-pommeled swords were no match for
this weapon; the Romans choked and died in moments, many with
their last pay of coins still slung in purses on their belts.

Nearby, a Persian soldier — perhaps the one who started the toxic
underground fire — suffered his own death throes, grasping
desperately at his chain mail shirt as he choked. [ Image
of skeleton of Persian soldier ]

These 20 men, who died in A.D. 256, may be the first victims of
chemical warfare to leave any archeological evidence of their
passing, according to a new investigation. The case is a cold
one, with little physical evidence left behind beyond drawings
and archaeological excavation notes from the 1930s. But a new
analysis of those materials published in January in the American
Journal of Archaeology finds that the soldiers likely did not
die by the sword as the original excavator believed. Instead,
they were gassed.

Where there's smoke

In the 250s, the Persian Sasanian Empire set its sights on taking
the Syrian city of Dura from Rome. The city, which backs up
against the Euphrates River, was by this time a Roman military
base, well-fortified with meters-thick walls.

The Persians set about tunneling underneath those walls in an
effort to bring them down so troops could rush into the city.
They likely started their excavations 130 feet (40 meters) away
from the city, in a tomb in Dura's underground
necropolis. Meanwhile, the Roman defenders dug their own
countermines in hopes of intercepting the tunneling Persians.

The outlines of this underground cat-and-mouse game was first
sketched out by French archaeologist Robert du Mesnil du Buisson,
who first excavated these siege tunnels in the 1920s and 30s. Du
Mesnil also found the piled bodies of at least 19 Roman soldiers
and one lone Persian in the tunnels beneath the city walls. He
envisioned fierce hand-to-hand combat underground, during which
the Persians drove back the Romans and then set fire to the Roman
tunnel. Crystals of sulfur and bitumen, a naturally occurring,
tar-like petrochemical, were found in the tunnel, suggesting
that the Persians made the fire fast and hot.

Something about that scenario didn't make sense to Simon James,
an archaeologist and historian from the University of Leicester
in England. For one thing, it would have been difficult to engage
in hand-to-hand combat in the tunnels, which could barely
accommodate a man standing upright. For another, the position of
the bodies on du Mesnil's sketches didn't match a scenario in
which the Romans were run through or burned to death.

"This wasn't a pile of people who had been crowded into a small
space and collapsed where they stood," James told LiveScience.
"This was a deliberate pile of bodies."

Using old reports and sketches, James reconstructed the events in
the tunnel on that deadly day. At first, he said, he thought the
Romans had trampled each other while trying to escape the tunnel.
But when he suggested that idea to his colleagues, one suggested
an alternative: What about smoke?

Fumes of hell

Chemical warfare was well established by the time the Persians
besieged Dura, said Adrienne Mayor, a historian at Stanford
University and author of "Greek Fire, Poison Arrows &
Scorpion Bombs: Biological and Chemical Warfare in the Ancient
World" (Overlook Press, 2003).

"There was a lot of chemical warfare [in the ancient world],"
Mayor, who was not involved in the study, told LiveScience. "Few
people are aware of how much there is documented in the ancient
historians about this."

One of the earliest examples, Mayor said, was a battle in 189
B.C., when Greeks burnt chicken feathers and used bellows to blow
the smoke into Roman invaders' siege tunnels. Petrochemical fires
were a common tool in the Middle East, where flammable naphtha
and oily bitumen were easy to find. Ancient militaries were
endlessly creative: When Alexander the Great attacked the
Phoenician city of Tyre in the fourth century B.C.,
Phoenician defenders had a surprise waiting for him.

"They heated fine grains of sand in shields, heated it until it
was red-hot, and then catapulted it down onto Alexander's army,"
Mayor said. "These tiny pieces of red-hot sand went right under
their armor and a couple inches into their skin, burning them."

So the idea that the Persians had learned how to make toxic smoke
is, "totally plausible," Mayor said.

"I think [James] really figured out what happened," she said.

In the new interpretation of the clash in the tunnels of Dura,
the Romans heard the Persians working beneath the ground and
steered their tunnel to intercept their enemies. The Roman tunnel
was shallower than the Persian one, so the Romans planned to
break in on the Persians from above. But there was no element of
surprise for either side: The Persians could also hear the Romans
coming.

So the Persians set a trap. Just as the Romans broke through,
James said, they lit a fire in their own tunnel. Perhaps they had
a bellows to direct the smoke, or perhaps they relied on the
natural chimney effect of the shaft between the two tunnels.
Either way, they threw sulfur and bitumen on the flames. One of
the Persian soldiers was overcome and died, a victim of his own
side's weapon. The Romans met with the choking gas, which turned
to sulfuric acid in their lungs.

"It would have almost been literally the fumes of hell coming out
of the Roman tunnel," James said.

Any
Roman soldiers waiting to enter the tunnels would have
hesitated, seeing the smoke and hearing their fellow soldiers
dying, James said. Meanwhile, the Persians waited for the tunnel
to clear, and then hurried to collapse the Roman tunnel. They
dragged the bodies into the stacked position in which du Mesnil
would later find them. With no time to ransack the corpses, they
left coins, armor and weapons untouched.

Horrors of war

After du Mesnil finished excavations, he had the tunnels filled
in. Presumably, the skeletons of the soldiers remain where he
found them. That makes proving the chemical warfare theory
difficult, if not impossible, James said.

"It's a circumstantial case," he said. "But what it does do is it
doesn't invent anything. We've got the actual stuff [the sulfur
and bitumen] on the ground. It's an established technique."

If the Persians were using chemical warfare at this time, it
shows that their military operations were extremely
sophisticated, James said.

"They were as smart and clever as the Romans and were doing the
same things they were," he said.

"It's easy to regard this very clinically and look at this as
artifacts … Here at Dura you really have got this incredibly
vivid evidence of the horrors of ancient warfare," he said. "It
was horrendously dangerous, brutal, and one hardly has words for
it, really."